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Temporal perception deficits in schizophrenia: integration is the problem, not deployment of attentions.

Su L, Wyble B, Zhou LQ, Wang K, Wang YN, Cheung EF, Bowman H, Chan RC - Sci Rep (2015)

Bottom Line: There was no difference between individuals with/without schizotypal personality disorder in temporal integration.Instead, we used both theoretical and empirical approaches to show that previous findings (using the suppression ratio to correct for the baseline difference) produced a systematic exaggeration of the attention deficits.Instead, we modulated the perceptual difficulty of the task to bring the baseline levels of target detection between the groups into closer alignment.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Psychiatry, University of Cambridge, Cambridge, UK [2] Neuropsychology and Applied Cognitive Neuroscience Laboratory, Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.

ABSTRACT
Patients with schizophrenia are known to have impairments in sensory processing. In order to understand the specific temporal perception deficits of schizophrenia, we investigated and determined to what extent impairments in temporal integration can be dissociated from attention deployment using Attentional Blink (AB). Our findings showed that there was no evident deficit in the deployment of attention in patients with schizophrenia. However, patients showed an increased temporal integration deficit within a hundred-millisecond timescale. The degree of such integration dysfunction was correlated with the clinical manifestations of schizophrenia. There was no difference between individuals with/without schizotypal personality disorder in temporal integration. Differently from previous studies using the AB, we did not find a significant impairment in deployment of attention in schizophrenia. Instead, we used both theoretical and empirical approaches to show that previous findings (using the suppression ratio to correct for the baseline difference) produced a systematic exaggeration of the attention deficits. Instead, we modulated the perceptual difficulty of the task to bring the baseline levels of target detection between the groups into closer alignment. We found that the integration dysfunction rather than deployment of attention is clinically relevant, and thus should be an additional focus of research in schizophrenia.

No MeSH data available.


Related in: MedlinePlus

(a) Human performance adapted from Cheung et al. (19); (b) Simulated performance on the AB task; (c) Suppression ratio of human data adapted from Cheung et al. (19); (d) Suppression ratio of the simulated data.
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f1: (a) Human performance adapted from Cheung et al. (19); (b) Simulated performance on the AB task; (c) Suppression ratio of human data adapted from Cheung et al. (19); (d) Suppression ratio of the simulated data.

Mentions: The model fitting was performed using the Matlab Statistics Toolbox (Mathworks). We set the noise parameter e to zero while fitting the above equation to the mean performance data of healthy controls19. The resulting parameters from the curve fitting for the control group are a = 2.1, b = 0.96, c = 0.86 and d = 0.87. We then kept the parameters a, b and d constant in the model and re-fitted the curve to the mean accuracy of the schizophrenia group in Chenug et al.19 by only varying the baseline parameter c. The result of the curve fitting was c = 0.7, reflecting a baseline performance decrease of 0.16 from healthy control. Hence, the entire blink curve of the schizophrenia group became lower than that of the control group but the basic shape of the blink curves and most importantly, the mean depth of the blink, are unchanged between groups (see Fig. 1a,b). By randomly re-sampling the noise parameter e, we have simulated the performance of 100 schizophrenia patients and 100 healthy controls to illustrate what would happen in a typical AB experiment. We found that there were significant main effects of group and of lag, but no significant group by lag interaction in our simulated populations. The two groups were significantly different at all lags in a simple effect analysis (paired t-test at each lag) due to the baseline shift in the post hoc analysis.


Temporal perception deficits in schizophrenia: integration is the problem, not deployment of attentions.

Su L, Wyble B, Zhou LQ, Wang K, Wang YN, Cheung EF, Bowman H, Chan RC - Sci Rep (2015)

(a) Human performance adapted from Cheung et al. (19); (b) Simulated performance on the AB task; (c) Suppression ratio of human data adapted from Cheung et al. (19); (d) Suppression ratio of the simulated data.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4419531&req=5

f1: (a) Human performance adapted from Cheung et al. (19); (b) Simulated performance on the AB task; (c) Suppression ratio of human data adapted from Cheung et al. (19); (d) Suppression ratio of the simulated data.
Mentions: The model fitting was performed using the Matlab Statistics Toolbox (Mathworks). We set the noise parameter e to zero while fitting the above equation to the mean performance data of healthy controls19. The resulting parameters from the curve fitting for the control group are a = 2.1, b = 0.96, c = 0.86 and d = 0.87. We then kept the parameters a, b and d constant in the model and re-fitted the curve to the mean accuracy of the schizophrenia group in Chenug et al.19 by only varying the baseline parameter c. The result of the curve fitting was c = 0.7, reflecting a baseline performance decrease of 0.16 from healthy control. Hence, the entire blink curve of the schizophrenia group became lower than that of the control group but the basic shape of the blink curves and most importantly, the mean depth of the blink, are unchanged between groups (see Fig. 1a,b). By randomly re-sampling the noise parameter e, we have simulated the performance of 100 schizophrenia patients and 100 healthy controls to illustrate what would happen in a typical AB experiment. We found that there were significant main effects of group and of lag, but no significant group by lag interaction in our simulated populations. The two groups were significantly different at all lags in a simple effect analysis (paired t-test at each lag) due to the baseline shift in the post hoc analysis.

Bottom Line: There was no difference between individuals with/without schizotypal personality disorder in temporal integration.Instead, we used both theoretical and empirical approaches to show that previous findings (using the suppression ratio to correct for the baseline difference) produced a systematic exaggeration of the attention deficits.Instead, we modulated the perceptual difficulty of the task to bring the baseline levels of target detection between the groups into closer alignment.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Psychiatry, University of Cambridge, Cambridge, UK [2] Neuropsychology and Applied Cognitive Neuroscience Laboratory, Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.

ABSTRACT
Patients with schizophrenia are known to have impairments in sensory processing. In order to understand the specific temporal perception deficits of schizophrenia, we investigated and determined to what extent impairments in temporal integration can be dissociated from attention deployment using Attentional Blink (AB). Our findings showed that there was no evident deficit in the deployment of attention in patients with schizophrenia. However, patients showed an increased temporal integration deficit within a hundred-millisecond timescale. The degree of such integration dysfunction was correlated with the clinical manifestations of schizophrenia. There was no difference between individuals with/without schizotypal personality disorder in temporal integration. Differently from previous studies using the AB, we did not find a significant impairment in deployment of attention in schizophrenia. Instead, we used both theoretical and empirical approaches to show that previous findings (using the suppression ratio to correct for the baseline difference) produced a systematic exaggeration of the attention deficits. Instead, we modulated the perceptual difficulty of the task to bring the baseline levels of target detection between the groups into closer alignment. We found that the integration dysfunction rather than deployment of attention is clinically relevant, and thus should be an additional focus of research in schizophrenia.

No MeSH data available.


Related in: MedlinePlus